MONTREAL – Comorbid mood and behavior problems that are present at an early age in children diagnosed with an autism spectrum disorder are associated with the frequency and severity of restrictive, repetitive, and stereotyped behaviors, a study has shown.
But those comorbid behaviors–including anxiety, hyperactivity, oversensitivity, and conduct problems–are not related to social or communication diagnostic criteria, Robin L. Gabriels, Psy.D., said at the 5th International Meeting for Autism Research.
Previous studies have demonstrated that people who have autism spectrum disorders (ASD) are at risk for various comorbid behavioral and psychiatric disturbances.
But at this point, it remains unclear whether such problems occur independently or result from pathologic processes that lead to autism, Dr. Gabriels said in a poster presentation.
And while it has been hypothesized that these comorbid problems somehow relate to the range of restrictive and repetitive behaviors and interests that characterize autism–including inflexible adherence to specific, nonfunctional routines or rituals, stereotyped and repetitive motor mannerisms, and self-injurious acts–data are lacking on how the specific behaviors relate, she said.
In an effort to gain insight into this association, Dr. Gabriels of the University of Colorado Health Sciences Center, Denver, and her colleagues compared the presence of frequent/severe repetitive behaviors and mood/behavioral problems in preschool children diagnosed with an ASD with those of a chronologic-age matched, typically developing control group.
The investigation relied on survey-based ratings by parents or other caregivers of 61 children (mean age 50.5 months) with an ASD who were recruited through the autism research registry at the University of North Carolina at Chapel Hill and 65 children (mean age 46.5 months) with typical development recruited through local preschools and day care centers.
The assessment measures included the Social Communication Questionnaire (SCQ), which screens for the presence of ASDs; the Repetitive Behavior Rating Scale-Revised (RBS-R), which measures stereotypy, self-injurious behavior, compulsions, rituals/sameness, and restricted interests; and the Nisonger Child Behavior Rating Form (NCBRF), which assesses behavior and emotional problems in children.
The investigators used unpaired t-tests for between-group comparisons of NCBRF scores for conduct, anxiety, hyperactivity, and overly sensitive behaviors, and Spearman's correlations to determine the relationship within the autism group between mood/behavior problems, autism symptoms, and repetitive behavior subtypes. Multiple regression analysis determined which NCBRF factor best predicted the total repetitive behavior score.
The data showed that the ASD group had significantly more mood and behavior problems than did the control group. Additionally, within the ASD group, “the RBS-R total score was significantly correlated with all four NCBRF subscales,” Dr. Gabriels said.
In contrast, none of the NCBRF subscales correlated significantly with the SCQ social or communication measures.
The multiple regression analysis of the individual NCBRF subscales relative to the RBS-R total score showed that anxiety was the best predictor of the presence of repetitive behaviors in the ASD group.
“Anxiety symptoms increased significantly with repetitive behaviors in the autistic group, but not in the typically developing group,” according to Dr. Gabriels.
This finding suggests that the presence of frequent and severe repetitive behaviors could signal increased anxiety in a child with an ASD, Dr. Gabriels said.
Furthermore, she said, such insight into these associations could help in the clinical assessment and management of patients by improving the accuracy of comorbid psychological diagnoses and ensuring appropriate treatment.
With respect to the anxiety finding, the male:female ratio in the ASD group was 9:1, “so it is possible that the strong relationship between more frequent/severe repetitive behaviors and symptoms of anxiety may reflect the tendency of males to have higher levels of externalizing behaviors than females,” Dr. Gabriels pointed out.
Further study is needed to gain more insight into the nature of the association, she said.